does new silicone bond with existing silicone?

[afex]

i'm planning on fixing two of the seals on the front vertical edges of my tank, but i dont want to mess with the other edges.

can i simply cut near the corners (leaving existing silicone in corner, and removing it along the edge) and put new silcone in place?

thanks in advance,
keith

 

[sabodish]

it will never hold..your best bet is to scrape off ALL of the old silicone, cleand the seams with acetone or laquer thinner and apply new beads.

 

[afex]

so you're saying there is ABSOLUTELY no way to reseal parts of a tank instead of the whole thing?

 

[Savatage]

I've done it with the bottom of a 90 and still holds 300lbs of sand, water, and 3 stingrays.

A seal is a seal. The silicone between the glass is what holds the thing together. The silicone that is spread along all adjoining edges is only to keep water from leaking out through pinholes between the sheets of glass.

 

[highquality]

also the new beads you will run will bond to glass on the edges so it will seal. i did that on an old leaky 55 i used for holding tank.

 

[sabodish]

new silicone will not bond to old silicone period. you can remove and replace a panel provided all the old silicone is removed from all the seams you are attempting to repair.

 

[Savatage]

Yes, I agree with you about the old adhering to the new, but I don't think he is trying to secure a new panel. He is only trying to add the extra water-tight benifit of smearing the already mated edges.

Just to set the record straight, if the silicone is cleaned with something like acetone or thinner, it will soften and clean the silicone enough for the new silicone to hold to the old. I am not, by any means, saying that the (new silicone to old) is strong enough to be used for structurally holding the glass. I am saying it will grab enough to still seal any pinhole leak-points.

Maybe I explained what I mean the wrong way. I hope you follow what I am attempting to explain here??????

 

[elliotklinger]

Existing silicone has to be clean and not worn out IE micro cracks, chipped, or shriveled. If the existing silicone is still in very good shape then new silicone'll applies just fine and still holds sealing property without any trouble.

 

[afex]

maybe this will help explain things

the silicone i want to replace is between the red lines

i want to leave all the other silicone in place.

can i just cut at the red lines and add a new bead which slightly overlaps with the old silicone at the cut and be sure it will hold?

 

[sabodish]

is the tank currently leaking there or do you just not like the look of the seam?

looking at that, i dont think there would be a problem cutting away the silicone on the inside of the tank and replacing it.

 

[afex]

while i was cleaning the empty tank i noticed some wear on the silicone. its not as thick in some places as it should be

i've never had problems with leaking, but want to avoid it

 

[Savatage]

Cut from corner to corner and reseal it. Thats all you have to do. Do NOT try to seal it from your red-line to red-line. Just remove the silicone all the way from one corner to the other and reseal it.

 

[Savatage]

Just to add one more comment. If it is for the cosmetic reasons, then you need not worry weather or not silicone holds to cured silicone. LOL

 

[afex]

well i wouldn't call it cosmetic. sure it looks worse but i'm concerned that if it continues to wear down then i will have to worry about leaking.

and if i cut from corner to corner, wouldn't that be the same as if the red lines were on the connecting edges?

 

[Savatage]

You could cut it at the red lines and be okay. Just make sure the old silicone that is left, is very clean. And make sure you smeer it over the top of the old.

 

[kmagyar]

Keith,
I am in the exact same situation. Did you do it? How did it work?

Thanks,

Keith

<a href=showthread.php?s=&postid=7579087#post7579087 target=_blank>Originally posted</a> by afex
well i wouldn't call it cosmetic. sure it looks worse but i'm concerned that if it continues to wear down then i will have to worry about leaking.

and if i cut from corner to corner, wouldn't that be the same as if the red lines were on the connecting edges?

 

[afex]

i ended up weighing my options and decided not to risk it.

one of the reasons why i think my silicone was wearing was due to my heavy-handedness when it came to cleaning the glass.

i decided to be more cautious around the edges and leave it be.

 

[kmagyar]

I just got off the phone with the people at All Glass Inc. They were little help as they could not understand the question. After several transfers, I was told they recommend stripping all silicone off then resealing it. Then I called a good friend of mine. He said that the LFS he worked at used to do this all of the time. Additionally, he told me that that bead is a secondary seal and does not hold to the overall structure of the tank. While we probably know that already, I was reminded by him that there is no inner bead on his 150 gallon reef. Just silicone between the joined glass. After the discussion, I may just do the same thing and leave it alone. Then again, I change my mind on a minute to minute basis . I will let you guys know if I wind up with 120 gallons on the floor, better looking verticle corners that dont affect the seals, or the same ripped up corners that I had before I dried the tank out.


Keith